Longitudinally fired walking beam furnace

ABSTRACT

A walking beam furnace having conveying means and support means structured so that an open expanse is provided beneath the work being treated. Direct fired burners are located so that they fire longitudinally into the open expanse between the work support means thereby uniformly heating the work.

United States Patent 91 Miyoshi et al.

[11] 3,820,946 1 June 28, 1974 LONGITUDINALLY FIRED WALKING BEAM FURNACE [75] Inventors: Ichiro Miyoshi, Osaka; Tetsuya Tokitsu, Takarazuka, both of Japan [73] Assignee: Midland-Ross Corporation,

Cleveland, Ohio [22] Filed: May 29, 1973 [21] Appl. No.: 364,692

[52] US. Cl. 432/121, 432/239 [51] Int. Cl. F27b 9/14 [58] Field of Search 432/57, 122, 123, 239- [56] References Cited UNITED STATES PATENTS 3,450,394 6/1969 Wilde et al. 432/122 9/1972 Enk 432/122 7/1973 Suydam 432/122 Primary Examiner-John J. Camby Attorney, Agent, or Firm-Henry Kozak [5 7] ABSTRACT A walking beam furnace having conveying means and support means structured so that an open expanse is provided beneath the work being treated. Direct fired burners are located so that they fire longitudinally into the open expanse between the work support means thereby uniformly heating the work.

3 Claims, 2 Drawing Figures PATENTED JUN 2 8 I974 Y'LONGITUDINALLY FIRED WALKING BEAM FURNACE BACKGROUND OF THE IVNENTION convey and support work such as slabs, sheet, blooms,

etc. through the furnace. The work is supported and conveyed on the movable beams and supported intermittently bythe stationary beams through the rising and lowering of the movable beams in a generally rota tional motion in the longitudinal plane.

In a furnace where work is conveyed in a plurality of rows, such as in a reheating furnace for heavy plate mill, or in a walking beam reheating furnace of the single row conveyance type which has a large width, work temperature distribution in the width of the furnace may become nonuniform. which nonuniformity ad versely affects the finished product.

Nonuniformity is caused by the fact that in the conventional walking beam type furnace, combustion in the bottom zone is carried out by burners mounted within the furnace sidewalls. That is, in the multi-row conventional furnace, the work is conveyed by means of movable beams and stationary beams and the work is heated by one set of burners mounted in the upper part of the furnace and by another set of burners mounted in bothside walls of the furnace bottom. Under these circumstances, products of combustion from the sidewall burners rise through the gaps between the work in the center of the furnace width to the top zone thereby resulting in overheating the ends of the work and, additionally, causing difficulty in the temperature control of the top zone.

In the case of narrow single row conveyance furnaces, central areas of work are overheated by flames from the side burners and, in contrast, in the case of wide furnaces, heat cannot reach the central portions of the work. In either case, extreme nonuniformity of work temperature distribution throughout the furnace resultsFurther, in the case of the side heating type furnaces, a complicated combustion controlof on-off ignition is required in order to obtain the requiredheat load of the furnace and to control heat'turndown;

In order to eliminate these defects, it is desirable to provide a burner system wherein the burners fire beneath the work in the longitudinal direction of the furnace. This is not feasible in conventional furnaces, as the space between movable posts, which support the conveying beams, and the stationary posts, which support stationary beams, is small and it is impossible to mount burners that will fire in the longitudinal direction of the furnace because the flame from the burners would fire directly upon the posts with adverse effect.

SUMMARY OF THE INVENTION This invention offers a walkingbeam type reheating furnace which resolves conventional problems associated with prior walking beam furnaces. In this invention, either the movable beam of the stationary beam is made in theform of a longitudinal rail, the other being made in the form of a saddle, and these two kinds of supports are alternately arranged in a virtual straight line when viewed in the longitudinal direction of the furnace. The arrangement is such that the saddle does not inhibit the movement of the movable beam, the saddle having an elevation greater than that of the movable beam when the latter is in its lowermost position and lower when the movable beam is in its uppermost position. Burners are mounted in the end walls of the lower zone of the furnace as well as in the upper zone of the furnace. These lower burners are directedinto the bottom zone in such a manner that the products of combustion flow in a longitudinal direction between the movable and stationary beam posts. Therefore, with this invention, both the edges and the central area of work are heated uniformly and temperature nonuniformity in the lateral direction associated with prior art walking beam furnaces is eliminated.

Since both top and bottom burners fire longitudinally, there is little interchange of atmosphere and the temperature in the top and bottom zones of the furnace can be controlled without greatly being affected by the other. Thus, precise and easy temperature control is available. Direction of flames in the longitudinal direction of the furnace makes the complicated heat control system of the type which is indispensable for the conventional side firing walking beam furnaces, unnecessary.

BRIEF DESCRIPTION OF THE DRAWING DESCRIPTION OF THE PREFERRED EMBODIMENTS furnace shown Referring now to the drawing, av walking beam. furnace utilizing the instant invention is shown generally at 10, having a housingcomprising a roof 12, end walls 14, side walls 16, and a floor 18, which floor has a plurality of openings 22 therein. Movable beam posts 20 are received within the openings 22 and extend vertically in the furnace. Secured to the lower ends of the posts 20 is a lift beam 24. Attached to the tops of each set of posts 20 is a pair of longitudinally extending movable support rails 26. Stationary beam posts 28 are alternately arranged to be in a virtual straight line with the movable posts 20 when viewed in the longitudinal direction of the furnace. Extending laterally between paired, spaced stationary posts 28 are a plurality of support members 30 in the form of saddles. Extending longitudinally upon the saddles 30 is a pair of laterally spaced stationary rails 32 which are located intermediate the movable rails 26. Such an arrangement becomes possible by the presence of the saddle 30 which allows the stationary rails 32 to be positioned as shown in the drawing.

Means is provided for moving the lift beam 24, and thereby the posts 20 and movable rails 26, in a rotational motion within a longitudinal plane as is well known in the art. Such means for example may comprise a pair of cam wheels 25, each of which is pivotally connected as at P" to suitable bracket means 240 on beam 24. Rotation of wheels 25 results in rotational movement of beam 24, posts and rails 26. The rotational movement would be clockwise as shown in FIG. 1. With such a motion, the support rails 26 lift the work W and move the same to the right as seen in FIG. 1, and then lower the work W to rest upon the stationary rails 32 after which the movable rails continue their rotational movement below the level of the stationary rails. In FIG. 2, the moving beam mechanism, comprising the lift beam 24, movable posts 20 and support rails 26, is shown on the left in its uppermost position and on the right in its lowermost position. It will be noted that 1 when the moving beam mechanism is in its uppermost position, the stationary rails 32 are located below the movable rails 26 whereas when the conveying mechanism is in its lowermost position, the converse is true.

Received within the upper portion of the end wall 14 is a plurality of burners 34 and received within the lower portion of the end wall is a second plurality of burners 36. As seen in FIG. 2, the distance between the laterally spaced posts 20, 28 can be made sufficiently wide so that the flame from the lower burners 36 may flow in the furnaces longitudinal direction without overheating the bottom of the posts 20, 28. That is, the work is heated not only by means of upper burners 34, bu also by means of burners 36 mounted along the end wall 14 provided in the bottom zone of the furnace. Since the burners 36 in the bottom zone are mounted so that the burner flame may flow in the longitudinal direction of the furnace within the span between the beam posts 20, 28, the burner flame will not impinge directly on the beam posts with the consequence that there is no damage to the same nor a shortening of their service life. Additionally, since both the upper and lower burners 34, 46 respectively fire longitudinally, there is less liklihood of atmosphere mixture. As a result, temperature control in the two zones is more easily controlled.

The work W is uniformly heated at its edges and central part by, as shown in this invention, making the burner flame at the bottom zone flow in the longitudinal direction of the furnace, which results in uniform temperature distribution that yields quality of the final products. Furthermore, the independent, precise and easy temperature control in the top and bottom zones of the furnace is available. It will be appreciated that burners may still be mounted on the sidewall 16 of the furnace if not required for any reason, and that the structure and alignment of the posts 20, 28 would not interfere with the installation of such sidewall burners.

What is claimed is:

1. In a walking beam furnace, the combination comprising: a longitudinally extending housing having a floor with a plurality of longitudinally elongated openings therein, sidewalls, end walls and a roof, at least one of said end walls having openings at both its upper and lower sections, a first plurality of vertically aligned, longitudinally spaced movable posts extending into said furnace through said floor openings, said movable posts being adjacent one of said sidewalls, a second plurality of vertically aligned, longitudinally spaced movable posts received within said floor openings, said second plurality of posts being spaced laterally relative to said first plurality of posts, a pair of longitudinally extending rails, one of said rails being secured to the upper ends of each one of said plurality of movable posts, lift beam means for supporting said posts and movable in a rotational motion in a longitudinal plane to raise and lower said posts, stationary work support means secured within said housing, said stationary work support means comprising stationary posts interspaced longitudinally with the movable posts of said first plurality and of said second plurality, said stationary posts being substantially in longitudinal alignment withsaid movable posts, the vertical locations of the top of said stationary work support means being above the vertical position of said rails when the movable posts are in their lowermost position and below said rails when said movable posts are in their uppermost position, and direct fired burners received within the openings of at least one of said end walls, said burners located in the bottom section of said end wall being positioned so as to fire between said laterally spaced posts.

2. In a walking beam furnace, the combination comprising: a longitudinally extending housing having a floor with a plurality of longitudinally elongated openings therein, sidewalls, end walls and a roof, at least one of said end walls having a plurality of openings within its upper and lower sections, a first plurality of ver-tically aligned, longitudinally spaced movable posts received within said floor openings, said movable posts being adjacent one of said sidewalls, a second plurality of vertically aligned, longitudinally spaced movable posts received within said floor openings, said second plurality of posts being spaced laterally relative to said first plurality of posts, a pair of longitudinally extending movable rails, each of said movable rails being secured to the upper ends of one of said plurality of vertically aligned, movable posts, lift beam means for supporting said posts and movable in a rotational motion in a longitudinal plane to raise and lower said posts, a first plurality of vertically aligned, longitudinally spaced stationary posts secured to said floor, said stationary posts being interspaced longitudinally with the movable posts of said first plurality and substantially in longitudinal alignment therewith, a second plurality of vertically aligned, longitudinally spaced stationary posts laterally spaced from said first plurality of stationary posts on a one-to-one relationship, said second plurality of stationary posts being substantially in longitudinal alignment with said second plurality of movable posts, laterally extending support members, each of said support members extending to and received upon a set of laterally paired stationary posts, the vertical locations of said support members being above the vertical position of said rails when the said movable posts are in their lowermost position and below said rails when said movable posts are in their uppermost position, and direct fired burners received within the openings of at least one of said end walls, said burners located in the bottom section of said end wall being positioned so as to tire between said laterally spaced posts.

3. The walking beam furnace of claim 2 wherein a pair of laterally spaced longitudinally extending stationary rails are received upon said lateral support members, and said stationary rails are located intermediate said longitudinally extending movable rails. 

1. In a walking beam furnace, the combination comprising: a longitudinally extending housing having a floor with a plurality of longitudinally elongated openings therein, sidewalls, end walls and a roof, at least one of said end walls having openings at both its upper and lower sections, a first plurality of vertically aligned, longitudinally spaced movable posts extending into said furnace through said floor openings, said movable posts being adjacent one of said sidewalls, a second plurality of vertically aligned, longitudinally spaced movable posts received within said floor openings, said second plurality of posts being spaced laterally relative to said first plurality of posts, a pair of longitudinally extending rails, one of said rails being secured to the upper ends of each one of said plurality of movable posts, lift beam means for supporting said posts and movable in a rotational motion in a longitudinal plane to raise and lower said posts, stationary work support means secured within said housing, said stationary work support means comprising stationary posts interspaced longitudinally with the movable posts of said first plurality and of said second plurality, said stationary posts being substantially in longitudinal alignment with said movable posts, the vertical locations of the top of said stationary work support means being above the vertical position of said rails when the movable posts are in their lowermost position and below said rails when said movable posts are in their uppermost position, and direct fired burners received within the openings of at least one of said end walls, said burners located in the bottom section of said end wall being positioned so as to fire between said laterally spaced posts.
 2. In a walking beam furnace, the combination comprising: a longitudinally extending housing having a floor with a plurality of longitudinally elongated openings therein, sidewalls, end walls and a roof, at least one of said end walls having a plurality of openings within its upper and lower sections, a first plurality of vertically aligned, longitudinally spaced movable posts reCeived within said floor openings, said movable posts being adjacent one of said sidewalls, a second plurality of vertically aligned, longitudinally spaced movable posts received within said floor openings, said second plurality of posts being spaced laterally relative to said first plurality of posts, a pair of longitudinally extending movable rails, each of said movable rails being secured to the upper ends of one of said plurality of vertically aligned, movable posts, lift beam means for supporting said posts and movable in a rotational motion in a longitudinal plane to raise and lower said posts, a first plurality of vertically aligned, longitudinally spaced stationary posts secured to said floor, said stationary posts being interspaced longitudinally with the movable posts of said first plurality and substantially in longitudinal alignment therewith, a second plurality of vertically aligned, longitudinally spaced stationary posts laterally spaced from said first plurality of stationary posts on a one-to-one relationship, said second plurality of stationary posts being substantially in longitudinal alignment with said second plurality of movable posts, laterally extending support members, each of said support members extending to and received upon a set of laterally paired stationary posts, the vertical locations of said support members being above the vertical position of said rails when the said movable posts are in their lowermost position and below said rails when said movable posts are in their uppermost position, and direct fired burners received within the openings of at least one of said end walls, said burners located in the bottom section of said end wall being positioned so as to fire between said laterally spaced posts.
 3. The walking beam furnace of claim 2 wherein a pair of laterally spaced longitudinally extending stationary rails are received upon said lateral support members, and said stationary rails are located intermediate said longitudinally extending movable rails. 